synced 2 MIN AGO
01 Record

CVE-2021-43538

By misusing a race in our notification code, an attacker could have forcefully hidden the notification for pages that had received full screen and pointer lock access, which could have been used for

UnratedPUBLISHEDCNA: mozilla
CNA base scoreUnratedNo CNA CVSS vector
View raw JSON

02 Description

By misusing a race in our notification code, an attacker could have forcefully hidden the notification for pages that had received full screen and pointer lock access, which could have been used for

03 Exploitation and scoring

Exploitation
Not assessed. CISA has not published an exploitation assessment for this record, and it is not in the KEV catalog. That is an absence of assessment, not a finding of no risk.
SSVC decision
Not assessed by CISA
EPSS probability
1.24% probability of exploitation activity in the next 30 days.
EPSS percentile
Equal to or higher than the score of 68.7% of scored records. A rank, not a probability.
NVD base score
4.3 (CVSS v3.x), scored by the NVD independently of the CNA.
NVD CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N
NVD analysis status
Modified. NVD last modified this record on 2026-06-17.
Red Hat severity
Important. Red Hat's rating for its own products, not a CVSS rating.

Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.

04 Metadata

Published
2021-12-08 21:20Z4 YR AGO
Last updated
2024-08-04 04:03Z2 YR AGO
Reserved
2021-11-08
Assigning CNA
mozilla
Record state
PUBLISHED
Severity
Not rated by the issuing CNA
CNA CVSS vector
Not published by the issuing CNA
Weaknesses
  • CWE-362Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')Class
  • CWE-1021Improper Restriction of Rendered UI Layers or FramesBase
Data version
5.1
Document digest
eb9c0f8a4601b5ac757301693544534f0088bc78ca8cf62d84335adab0a5f869

05 Affected products

VendorProductVersionsPlatforms
MozillaThunderbird< 91.4.0—
MozillaFirefox ESR< 91.4.0—
MozillaFirefox< 95—

06 References

07 Fixed in

AlmaLinux 8

  • firefox
    Fixed in 91.4.0-1.el8_5.alma
  • thunderbird
    Fixed

    A version is affected if any line below covers it.

    • Affected before 91.4.0-2.el8_5.alma
    • Affected before 91.4.0-2.el8_5.alma.plus

Source: AlmaLinux, AlmaLinux OS. Copyright (c) 2023 AlmaLinux OS. Licensed under MIT License. Received through OSV.dev. Reformatted by exploit.cc.

Arch Linux

  • firefox
    Fixed in 95.0-1
  • thunderbird
    Fixed in 91.4.0-1

Source: Arch Linux Security Tracker, the Arch Linux security team. Reformatted by exploit.cc.

CloudLinux 8

  • firefox
    Fixed in 91.4.0-1.el8_5.alma
  • thunderbird
    Fixed

    A version is affected if any line below covers it.

    • Affected before 91.4.0-2.el8_5.alma
    • Affected before 91.4.0-2.el8_5.alma.plus

Derived from AlmaLinux 8. Partial coverage: only packages taken from AlmaLinux 8 are listed.

Source: CloudLinux errata, CloudLinux Inc. Derived from: AlmaLinux, AlmaLinux OS. Copyright (c) 2023 AlmaLinux OS. Licensed under MIT License. Received through OSV.dev. Reformatted by exploit.cc.

Debian 12

  • firefox-esr
    Fixed in 91.4.0esr-1
  • thunderbird
    Fixed in 1:91.4.0-1

Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.

Debian 13

  • firefox-esr
    Fixed in 91.4.0esr-1
  • thunderbird
    Fixed in 1:91.4.0-1

Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.

Debian 14

  • firefox-esr
    Fixed in 91.4.0esr-1
  • thunderbird
    Fixed in 1:91.4.0-1

Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.

Ubuntu 18.04 LTS

  • firefox
    Fixed in 95.0+build1-0ubuntu0.18.04.1
  • mozjs38
    No fix yet
  • mozjs52
    No fix yet
  • thunderbird
    Fixed in 1:91.5.0+build1-0ubuntu0.18.04.1

Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.

Ubuntu 20.04 LTS

  • firefox
    Fixed in 95.0+build1-0ubuntu0.20.04.1
  • mozjs52
    No fix yet
  • mozjs68
    No fix yet
  • thunderbird
    Fixed in 1:91.5.0+build1-0ubuntu0.20.04.1

Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.

Ubuntu 22.04 LTS

  • firefox
    Fixed in 95.0+build1-0ubuntu1
  • mozjs78
    No fix yet

Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.

A release or ecosystem missing from this list has no record here. It may be unaffected or not covered by the source. Source notices and licences.